Pumping mechanism



July 25,1933. H T, BLOM 1,919,195

PUMPING MEcHANIsM Filed Oct. 6, 1931 Br 41m f Patented July. 25, 1.9.33

.nn-mis fr. zum, or 'memoir om, incisivi, Assiifon 'rollsytmmvm MACHINERYUOMANY, A1 oon-P01'uul'roiir"` `or MAvssAcHUsE'r'rs i,

' fummo g msn .A'p'pmation 'md nowhere, 193i. "serial No. 567,240.`

i i My invention relstestopumping-mechanisms, and more particularly to Vair com# pressors and `unloading means therefor. @ne

` of the l'standard methods f of unloading air il compressors isi-hy.connectingthe` interior Vof the cylinder `continuously'y withthe `fgtnfiosphare, las' through the 'compressor intake.` when it 's3 4desired tointerrupt the pumping` action. A usual method of acmplishing l this -rcsulti's to open, and holdin-open position;- thesinlet ,valves :of the compressorjwhich isftobe unlocded. In large-size compressors, where the` volume ofcir Vhandled is very great, vit is. obviously neccessary,L in 1 order :thet the power lost through `drawing in' Y and dis,- charging `air through the. Vinlet valves While the compressor isvunloaded mayfbekept s t af minimum,y to provide devices Afor opening large numbersof inlet valves; and-os'iccordingf` l multiplication Vof parts Ais;.enconntered. (lbviouslv,V moreover",vr it would be 'beneficial to. `avoid `this ymultiplication of parts sind .tof

attain, lat the same time, maximum freedom 'of AHowi-nvvaI-'dly` and outwardly `with respect to the compressor lcylinder.- y, y fltli'san, object ofmyinve 'tiontq rovide aIymprOved ypumping mechanism.. t is an- Qtherfobject offmyinvention to `provide all; improvedl unloalding' mechanism s presser which permits prccticallyree communication between the interior of the c i.1inder andthe :itosphere during periods o unloading.. Ity isa: further object of my `invention .to provide an` improved- `unloading mechanism :for a con'rpi'ess'orv in' lwhich with a single .,vzgvlve,4 even in largesize compressors', an loaded kaccording tothe method vvvhqichtfhe i'ntel'orof` the4 compressorv is .connected .freely Withthe atmosphere. It is a;4 furtherobject of m .inventiontoprovide ycngimproved unf,- loading mechanisinf for wircoin lessors rwhich meyl be, employed -vvithequal acility in sinle stage and multi-stage compressors-Land 1n Vwhich either 'manual' or automatic control ma. be selectively uvailedof.-l .Otherobj'ects `an 'advant'cgesof the invention will Subsc quentl appear.

nt ev accom anying drawin ,.-invvhich,

89 for purposeso illustration, yIV cve shown end .of a. compressor mavgbeA Wholly -Aunone form which` my inracticeg- ,i f i, ig. 1 is a side elevation of @compound ment of the invention l,is incorporated; Fig. 2 is cn 'axial sectionthro ghthe low pressure cylinder of the `air compressor, illustretedin Fig. 1, the section being taken invention may v`assume compressor in vWhichthe illustrative eniloodi-i I on `aplene corresponding to the line 2 -A-2 .of

Fig. 3, with parts r'IgcIIlOVfd i v. Fig. 3 is a vertical transverse section taken on line'l--Bl of Fig. 2';

. 'Fig is an elevation ofevalve;` y

Fig. 5y is cusectionthroughthe unloading mechanism operating `devices taken on the line-' of Fig. 3. l y

eferrin-g to the drawing, and particularly, F 1., it Will he noted that an air compressor 1 having@` low pressure cylinder ande. high pressure cylinderB connected throufghfan intercooler 4, is arranged to take aJirr through an intake connection `5 and deliver it after l compression toa. discharge line 6. The low pressurecylinder, Whose details oi'constrvuction al'one are illustrated, comprises fr cylin'- derfmember, 7 having a. bore ,VSYWithin which I apiston.isreciprocable by a. piston rod 10.

'Headslh of which one is vshown in section in Fig.'2,comprises spaces 12in c ommunication.y

as at 133- vvith a,` chamber 14 in the cylinder casting Whiclrcommunicates freely with vthekintake 5 of the compressor.

and dischargefvalve units, generally `des'ig-l natejd 15,1 crearrlangedlat the top and around substantial portions ofthe sides'of the cylinder heard,v a ,larve number` yoli these `unitsbeing` used'fn view of the size of the compressor anjd the im ortaince of maintaining the velocity of voir. kovv throu h the ports as low `espossible. These com'` ined' linlet and ldischarge v'lve units communicate l with the-bore of, the cylinder Ythrough ports` [16. Each of vthese units comprises `an inlet y valve .unit 17 @nd .l discharge valve .unitwlSyand the discharge side'of the latter communicates `with av channber 19 Ein' the` cylindery casting,= which chamber isfconnected,as at 20,With theinter'coole- Theiinnerwall 22( of catch head'mernber `is Combined inl et i plane seat surface 24 preferably slightly recessed Within the forward inner surface of the tions 27, is supported in contact with the seat surface 24'. The valve member 25 may preferably be formed of saw steel or the like, and .may be reinforced, if desired, .either at its inner or outer periph'eries by a strengthening ring. Such a ring is shown at 28'securedaty the inner periphery of the valve 25 in Figs.

`2 and 4. To insure that the valves25 Wil-l remain upon their seats, guides 29l secured, as by screws 30, to the inner side of the heads 11, may be employed, if desired, these guides having lips 31 overlapping an edge of the valve. These guides may be arranged either at the inner periphery, atthe outer periphery, or to cooperate With both'peripheries of the valves.

To control the position ofthe valves I25,' combined manually operable and automati# cally operable controlling means are provided. Herein, secured to each of the valve discs 25 I have shown arcuate racks 32l With- Which beveled-pinions33` carried on radially extending shafts 34 cooperate. The outer ends of the shafts 34 carry spur gears 35, and a rack 36 engages each pinion The racks are carried by Aplunger members 37 normally held by a. spring 38 in a position to maintain the valves 25 in port-closing position. The plungers 37 are reciproca-ble in Cylinder members 40 carried by the heads 11, and the plung` Y ers are formed at one end as pistons; herein in Fig. 5 the plunger being shown as provided With a double packed cup Washer type piston 41. It is obvious that since, in the high pressure cylinder at least, there is a possibility of air escaping to the interior ofthe cylinders 40 at intercooler pressure, it is desirable that the pistons preclude the fiow of air in both directions. Other packing devices obviously may be used, and'` if desired theplunger 37 may be arranged to cooperate With a valve seat When in its positionshown in Fig.` 5. The plunger 37 may be manually moved, if desired, by the handle 43 and screw'44, Whose inner end is adapted to engage the right hand side of the piston in Fig. 5. A. 'lock nut'46 may hold the parts in any desiredV position.

To permit automatic controlof the'plungers 37, a pilot'valve 47 receiving air through a passage'43 fromthe discharge line ofthe compressor is provided to supply air to operate the plungers 37 when the compressor discharge pressure passes a predetermined'desired maximum and to vent the air previously supplied when thecompressor discharge pressure falls below a predetermined desired minimum. The pilot valve 47 controls in thismanner the flow of air through apass'age 49 which is connected by pipes- 50, 51 and branch connections 52, 53 and 54, 55 with the unloading plungers 37 associated with the 10W and high pressure cylinders respectively.

The descriptionv heretofore given has related primarily to the details of construee tion of but one end of the loW vpressure cylinder; but obviously both ends of thiscylinder may be similarly equipped, and both ends of the high pressure cylinder may be provided With generally similarA unloading devices forthe purpose of 'connecting the interior of the high pressure kcylinder constantly With the intercooler duringl unloading, and such mechanisms are shown in vconnection With the high pressure cylinder, generallyat, 57 supplied'with--fiuid through thepipes54,f55.-"-f\ i It will be understoodvfrom What'has been said that When 'it lis desired that the `compressor shall operate in anormal manner andl draw in andy compress air :to' a desiredA dis` charge pressure, the valvesf25 will 'bejp'osvi-M tion'ed upon their seats 24 in Ysuch` manner that the 'port closure portions 27 overli'e' the passages and `With-thevalves in that position air Will be drawn through -the vintake 5, the chamber 14, passage 13, chamber 12,"the inlet valve unit 17 into the ycylinderthrough ports 16, be compressed therein, .discharged throughv discharge valve units 18 to vchamber 19 and through passage 20 tothe intercooler 4, from Which it Will be 'drawn' into thev high pressure cylinder 3 and there compressed 'in a manner which will be clear from-'Wh`athas been described Withfrespect to theloW pressure cylinder. When the compressoris`un` loaded, Which may b'e effected'by manualv ro` tation of the v screw 44, or which vmay` be effected automatically lWhen.' theA compres-4` `sor discharge pressure exceeds the predemuni'clatio n,i through the portsl 26- and*A passages 23, chamber 12, passage`13, chamber v14, and intake 'connection 5,With' the atmosphere and correspondinglythe'high pressure *cylini der bore will be placed in free'communica'- tion with thefinterior ofthe intercooler in` a manner which'y will beobvious.'

It Will be clear thatiby the mechanismdescribedand illustrated, I rhave provided'a very "simple, desirably controlled `and very efficient4 unloading mechanism,"- `in Vwhich 'single movable valves provide comin-unical tioncof large vflow area` between the cylinder bore andthe spaces with Whichtheirv intakes communicate. It will be evident/that the iizo mechanism is inexpensive, comprises a mininum number of parts, is not likely to reduce eiciency by reason of leakage, but instead, because of its simplicity and the moderate flexibility of the valves, to insure a tight seal when the unloading valves are in :closed position. It will further be noted that not only are the large numbers of individual unloading devices associated with separate inlet valves eliminated, but that the most direct possible flow between thek interior of each cylinder and its intake space is provided.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form is shown 'for purposes of illustration only and that the invention embodied in various may be modified and other forms without departing from its spirit or the scope of the appended claims. What I claim Vas new and desire to secure by Letters Patent is: i

1. In a compressor, inder having a head, said cylinder for controlling the inlet of fluid thereto and the discharge of fluid therefrom during normal operation, and separate `compressor unloading means for providing a direct communication between the interior of said cylinder and a space at its intake pressure including a rotatable unloading valve coaxial with said head and carried thereby and having operating means.

2. In a compressor, in combination, a cylin combination, a cylinder, means associated therewith for controlling the inlet of fluid thereto and the dis-, charge of fluid therefrom during normal operation, and separate compressor unloading means for providing adirect communication between the interior of said cylinder and a space at its intake pressure including Va rotatable unloading valve coaxial with said cylinder.

3. In a compressor, in combination, a cyl-` inder, means associated therewith for controlling lthe inlet'of fluid thereto and the discharge of fluid therefrom during normal operation, and separate compressor unloading means for providing a direct communication between the interior of said. cylinder and a space at its intake pressure including a rotary 1 `said valve, a reciprocable plunger carried by Y' means associated with cylinder thereto and the discharge of fluid `therefrom during normal operation,

` eration,

disc unloading valve coaxial with said cylinder.

4. In a compressor, in combination, a cyl-fjf inder, means associated therewith for controlling the inlet of fluid thereto and the discharge of fluid therefrom during normal operation, and separate compressor unloading means for providing a direct communication between the interior of said cylinder and a L space at its intake pressure including a ported rotary discunloading valve coaxial with said cylinder. y f 1 f 5. In a compressor, in combination, acylinder member, a cylinder head, inlet and discharge valves, an unloading device carried by .30 the cylinder headand including a valveseat formed on the head, a rotary unloadingvalve cooperating with'said seat, a rack-carried by.

said head, means for effecting reciprocation of said plunger, and gearing connections between said plunger and said rack.

6. In a pump, in combination, a cylinder havinga head, means associated withusaid cylinder for controllingpthe `inlet offiuid thereto and the discharge of fluid therefrom during normal operation, and separate pump unloading means including an unloading valve coaxial with said cylinder for effecting unloading thereof. j i i' 7 In a pump, 'n combinatioma cylinder. having a head, means? associated with said yfor controlling theinlet of fluid and'separate pumpv H Y unloading means including lan :unloading valve rotatable on an axis in the same'line with the cylinder axis for effecting unloading.

8. In a pump, in combination, a cylinder .i having a head, a piston having a pistonrod n A and reciprocable insaid cylinder,'means associated with said cylinder for controlling the inlet of 'liuid thereto and the discharge of fluid therefrom during normal pumping opand unloading means for said pump including a rotatable annular," unloading valve having a 'central openinglarger than the diameterof said piston rod and surrounding the axis of the cylinder. f

` l` HJALMAR T. 

